Differential enhancement of collagen crosslink excretion in cases of osteosarcoma and chondrosarcoma

Hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) are markers of collagen absorption and LP is specific for collagen type I in bone. In the present study we evaluated the concentration of HP and LP in urine of patients with osteosarcoma ( n=20; age range 16-49 years) and chondrosarcoma ( n=15; age range 18-70 years). The values were compared with those obtained from 74 healthy controls (age range 16-83 years). The range and upper limit of normal values (HP(max) and LP(max)) were measured in our control group. High performance liquid chromatography (HPLC) was used to determine concentrations of HP and LP (nmol/mmol creatinine). The average urinary HP concentrations were significantly increased in patients with osteosarcoma ( p=0.001) and chondrosarcoma ( p<0.001), whereas HP remained within the normal range in approximately half of the patients. The average urinary LP concentrations were not increased in osteosarcoma and chondrosarcoma patients as compared with the control group. Further studies in a large group of patients are necessary to evaluate whether HP might be a valuable marker of prognosis, and if its urinary concentration can be correlated to tumour burden.